1. Field of the Invention
The present invention relates to a light-emitting diode, and in particular to an anode connection structure of an organic light-emitting diode and a manufacturing method thereof.
2. The Related Arts
An organic light-emitting diode display (OLED), which is also referred to as an organic electroluminescent diode, is a novel displaying technology of which the development was dated back to the middle of the 20th century. The organic electroluminescent diode has various advantages over a liquid crystal display, such as being fully solid state, active emission of light, high brightness, high contrast, being ultra thin, low cost, low power consumption, fast response, wide view angle, wide range of operation temperature, and being capable of flexible displaying. The structure of an organic electroluminescent diode generally comprises a substrate, an anode, a cathode, and an organic function layer and the principle of light emission thereof is that multiple layers of organic materials that are of extremely small thickness is formed between the anode and the cathode through vapor deposition, whereby positive and negative carriers, when injected into the organic semiconductor films, re-combine with each other to generate light. The organic function layer of the organic electroluminescent diode is generally made up of three function layers, which are respectively a hole transport layer (HTL), an emissive layer (EML), and an electron transport layer (ETL). Each of the function layers can be a single layer or more than one layer. For example, the hole transport layer may sometimes be further divided into a hole injection layer and a hole transport layer and the electron transport layer may also be divided into an electron transport layer and an electron injection layer. However, they are of substantially the same function and are thus collectively referred to as the hole transport layer and the electron transport layer.
Currently, the manufacture of a full-color organic electroluminescent diode is generally done with three methods, which are RGB juxtaposition and individual emission method, white light in combination with color filter method, and color conversion method, among which the RGB juxtaposition and individual emission method is most promising and has the most practical applications. The manufacturing method thereof is that red, green, and blue use different subject and object light-emitting materials.
The organic light-emitting diodes can be classified in two types, according to the method of driving, which are active driving and passive driving, namely direct addressing and TFT (Thin-Film Transistor) matrix addressing. The active driving type organic light-emitting diode is the so called active matrix organic light emitting device (AMOLED).
The AMOLED has a pixel circuit and a compensation circuit that are much more complicated than those of a liquid crystal display (LCD) and thus, for the conventional AMOLED products, the available number of pixels per inch (PPI) is less than 280, rendering the resolution relatively low.
Referring to FIGS. 1 and 2, schematic views are given to show a conventional anode connection structure of an organic light-emitting diode. An anode 100 is electrically connected to a low-temperature poly-silicon layer 50 by driving the source/drain terminal 300 of the thin-film transistor. Due to the arrangement of a metal layer of the source/drain terminal 300, the distance between switching thin-film transistors on the two sides is increased, whereby the area of the pixel is relatively large and thus the number of pixels per inch is reduced, leading to a relatively low resolution.